OBB complexes have a general formula of: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 represent hydrogen, a halogen atom, or a straight chain or branched chain alkyl group of 1 to 5 carbon atoms, and n and m are integers between 1 and 6.
These complexes can be synthesized according to applicant's U.S. Pat. No. 4,397,092.
In order to isolate OBB acid, these complexes may undergo a treatment with boiling water or dilute alkali to destroy the HF and BF.sub.3. Recovery of the HF/BF.sub.3 combination catalysts, which are used in the synthesis of these complexes from anthraquinone as described in applicant's above-mentioned patent, cannot be performed economically.
These complexes can also be decomposed by heating at 150.degree. to 200.degree. C. over an extended period of time, but such treatment simultaneously causes an almost total degradation of the OBB acid itself. Also, any water formed during the decomposition of the OBB acid further combines with the HF and BF.sub.3 thus rendering the catalyst unsuitable for recycling.
It is possible to limit the decomposition of the OBB acid by the extended heating of the complex under a vacuum at a lower temperature, such as 50.degree. to 100.degree. C., but the OBB acid will retain part of the catalyst which makes this process uneconomical. If the complex is heated at low temperatures in an inert solvent, it is not possible to recover all of the catalysts and it causes an important degradation of the OBB acid.